The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Vehicle systems include a plurality of subsystems, including by way of example, engine, transmission, ride/handling, braking, HVAC, and occupant protection. Multiple controllers may be employed to monitor and control operation of the subsystems. The controllers can be configured to communicate via a controller area network (CAN) to coordinate operation of the vehicle in response to operator commands, vehicle operating states, and external conditions. A fault can occur in one of the controllers that affects communications via a CAN bus.
Topology of a network such as a CAN refers to a connective arrangement among network elements, and preferably includes a plurality of nodes having interconnected or dispersed power, ground or communications links. A physical topology describes arrangement or layout of physical elements including links and nodes, wherein nodes include controllers and other connected devices and links include either power, ground or communications links in the form of suitable cables, wires, printed wiring boards (PWBs), printed circuit boards (PCBs), flexible strips, and the like. A logical topology describes flow of data messages, power or grounding within a network between nodes employing power, ground or communications links. Known CAN systems employ a bus topology for the communication connection among all the controllers that can include a linear topology, a star topology, or a combination of star and linear topologies. Known high-speed CAN systems employ linear topology, whereas known low-speed CAN systems employ a combination of the star and linear topologies. Known CAN systems employ separate power and ground topologies for the power and ground lines to all the controllers. Known controllers communicate with each other through messages that are sent at different periods on the CAN bus.
Known systems detect faults at a message-receiving controller, with fault detection accomplished for the message using signal supervision and signal time-out monitoring at an interaction layer of the controller. Faults can be reported as a loss of communications, e.g., a loss of a communicated data message. Such detection systems generally are unable to identify a root cause of a fault, and are unable to distinguish transient and intermittent faults. One known system requires separate monitoring hardware and dimensional details of a physical topology of a network to effectively monitor and detect communications faults in the network.
A fault signature for a network topology can be generated off-board and flash-programmed into a system during vehicle manufacturing and assembly. In one embodiment of a vehicle system, there can be a plurality of topology variations due to differing vehicle and controller configurations. This adds complexity of timing management in a vehicle manufacturing plant and may reduce the manufacturing throughput.